From: Phrogz <gavin@...>
Date: 2006-12-26T05:35:08+09:00
Subject: Re: Strange about Array#each_index

Robert Klemme wrote:
> each_index always *returns* the receiver (i.e. the Array or whatever you
> invoke that method on) and each_index *passes* every index to the block.

A few more examples to help clarify:

  # Do nothing in the block and see what is returned
  p %w|a b c|.each_index{ }
  # => ["a", "b", "c"]

  # How about the #times method?
  p 3.times{ }
  #=> 3
  # Apparently it returns the last index passed to the block

  # Let's write our own
  def foo; yield; end
  p foo{ 'a' }
  #=> 'a'
  # Our method returns whatever the block returns

  # Now, let's return something else
  def foo
    yield 42
    'bar'
  end
  p foo{ |x| p x }
  #=> 42
  #=> "bar"

That last example is like each_index; it doesn't matter what you do in
the block, the method ends up returning a different value from what
your block returns.